1. Field of the Invention
The present invention relates to semiconductor light emitting devices, and more particularly, to a semiconductor light emitting device and a method for fabricating the same.
2. Description of the Related Art
In general, a light emitting diode (LED) uses the characteristics of a compound semiconductor to convert electrical energy into infrared ray signals, visible ray signals, or light signals. A light emitting diode is a kind of electroluminescence (EL) device, and a light emitting diode based on a Group III-V compound semiconductor is being practically used. A Group III nitride-based compound semiconductor is a direct-transition semiconductor. Because Group III nitride-based compound semiconductors can operate in a stable manner, Group III nitride-based compound semiconductors are widely used in light emitting devices such as light emitting diodes (LEDs) and laser diodes (LDs).
Research is being conducted into improving the light emission efficiency (i.e., the light extraction efficiency) of a semiconductor light emitting device by forming a concavo-convex structure in a light extracting region of a light emitting device. The propagation of light is restricted at the interface between material layers having different refractivity. When light propagates from a semiconductor layer with high refractivity (n>1) to an air layer with low refractivity (n=1), the light must be incident on the flat interface at less than a predetermined angle (critical angle) to the vertical direction of the interface. If light is incident on the interface at more than a predetermined angle to the vertical direction of the interface, total reflection occurs in the flat interface, thus significantly reducing light extraction efficiency. In order to prevent this, attempts have been made to introduce a concavo-convex structure in the interface.